Cutting apparatus for welding machine

ABSTRACT

To provide a cutting apparatus for a welding machine, which is less costly, at least one of each of upper blade portion ascending/descending guide units, a lower blade portion ascending/descending guide unit and an ascending/descending guide unit for holding a clearance between the upper and lower blade portions is used in common as a co-use ascending/descending unit out of the plurality of ascending/descending guide units. Also, there is provided a hydraulic drive unit normally depending upon the operation of the upper blade portion ascending/descending link unit and working as a drive source for the upper blade portion ascending/descending link unit when necessary, in conjunction with the upper blade portion or the upper blade portion ascending/descending link unit.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a cutting apparatus for awelding machine, provided with a pair of upper and lower blade portionsfacing each other, an upper blade portion ascending/descending linkmeans for moving the upper blade portion up and down to the lower bladeportion, a plurality of ascending/descending guide means for guidingabutment between the upper and lower blade portions and anascending/descending drive means for ascending and descending the upperblade portion through the upper blade ascending/descending link means,and for example, to a cutting apparatus for a seam welding machine forbonding a tail end portion of a leading plate and a tip end portion of atrailing plate in a process line of metal plates.

[0003] The entire content of the basic Japanese Patent Application fromwhich the priority under the Convention is claimed in this applicationis hereby incorporated by reference into this application.

[0004] 2. The Related Art

[0005] The conventional technology will now be described with referenceto FIGS. 12 to 14.

[0006] FIGS. 12 to 14 schematically show a cutting apparatus for amushroom welding machine used in a process line of metal platesdisclosed in Japanese Examined Utility Model Publication No. Sho62-39902, further including a current structure for showing details.

[0007]FIG. 12 is a frontal view, FIG. 13 is a cross-sectional view takenalong the line A-A of FIG. 12 and FIG. 14 is a cross-sectional viewtaken along the line B-B of FIG. 13.

[0008] In the cutting apparatus for a welding machine shown in FIGS. 12to 14, first of all, a tail end portion of a leading plate 1 and a tipend portion of a trailing plate 2 are stopped within a mushroom weldingmachine, and thereafter, are fixed by leading plate clamps 3 andtrailing plate clamps 4.

[0009] After the fixation, a lower blade holder 8 (hereinafter alsoreferred to as lower blade portion) on which mounted are a leading platecutting lower blade 6 and a trailing plate cutting lower blade 7 israised within a carriage C frame 5 as an apparatus frame shown in FIG.13, and at the same time, an upper blade holder 11 (hereinafter alsoreferred to as upper blade portion) on which mounted are a leading platecutting upper blade 9 and a trailing plate cutting upper blade 10 islowered within the frame, so that the tail end portion of theabove-described leading plate 1 and the tip end portion of the trailingplate 2 are cut in parallel prior to the welding operation.

[0010] When the cutting operation has been carried out, the lower holder(lower blade portion) 8 is lowered, and at the same time, the upperholder (upper blade portion) 11 is raised so that a double cut shearthat has cut the tail end of the leading plate 1 and the tip end of thetrailing plate 2 is returned back to the original position. After that,other devices within the welding machine take further steps for welding.

[0011] The above-described lower blade portion designates a portionincluding the leading plate cutting lower blade 6, the trailing platecutting lower blade 7 and the lower holder 8, and the above-describedupper blade portion designates a portion including the leading platecutting upper blade 9, the trailing plate cutting upper blade 10 and theupper holder 11.

[0012] In FIG. 13, on the lower blade portion side, the lower bladeholder 8 of the lower blade portion is guided by a guide bearing 12 aand a guide bearing 12 b mounted on the carriage C frame 5 as theapparatus frame and the ascending/descending guide means is composedmainly of a guide shaft 13 a and a guide shaft 13 b so as to be movablein the vertical direction.

[0013] The lower blade ascending/descending link means will now bedescribed.

[0014] First of all, on the lower blade portion side, one side of a link14 a is coupled rotatably with a shaft 15 a mounted on a lower side ofone end side of the lower holder 8, whereas one side of the other link14 b is coupled rotatably with a shaft 15 b mounted on a lower side ofthe other end side of the lower holder 8.

[0015] Also, one end side of a link 16 a is coupled rotatably with ashaft 18a fitted in a bracket 17 a mounted on the lower side of thecarriage C frame 5, whereas one end side of the other link 16 b iscoupled rotatably with a shaft 18 b fitted in a bracket 17 b mounted onthe lower side of the carriage C frame 5.

[0016] Also, the link 14 a and the link 16 a are coupled rotatably withone shaft 20 a of shaft 20 a and shaft 20 b provided on both sides of alink 19, whereas the link 14 b and the link 16 b are coupled rotatablyon the other shaft 20 b to form a parallel link mechanism.

[0017] The ascending/descending drive means on the lower blade portionside will now be described.

[0018] A crevice type cylinder 23 is used as the ascending/descendingdrive means on the lower blade portion side. A crevice portion of thecrevice type cylinder 23 is coupled rotatably with a shaft 22 engagedwith a bracket 21 mounted on the carriage C frame 5 as the apparatusframe.

[0019] This crevice type cylinder 23 is coupled with the link 19,constituting the lower blade portion ascending and descending means,through a tip end metal member 24 mounted at the tip end of a piston rodthereof and a shaft 25 engaged with this tip end metal member 24.

[0020] The upper blade portion side ascending/descending guide meanswill now be described.

[0021] On the upper blade portion side, a guide shaft 27 a and a guideshaft 27 b are arranged so that the upper blade holder 11 is guided by aguide bearing 26 a and a guide bearing 26 b mounted on the carriage Cframe 5 as the apparatus frame so as to be movable vertically.

[0022] The upper blade portion ascending/descending means will now bedescribed.

[0023] On the upper blade portion side, one side of a link 28 a iscoupled rotatably with a shaft 29 a mounted on an upper side of one endside of the upper holder 11, whereas one side of the other link 28 b iscoupled rotatably with a shaft 29 b mounted on an upper side of theother end side of the upper holder 11.

[0024] Also, one end side of a link 30 a is coupled rotatably with ashaft 32 a fitted in a bracket 31 a mounted on the upper side of thecarriage C frame 5, whereas one end side of the other link 30 b iscoupled rotatably with a shaft 32 b fitted in a bracket 31 b mounted onthe upper side of the carriage C frame 5.

[0025] Also, shafts 34 a and 34 b are provided on a link 33. The link 28a and the link 30 a are coupled rotatably with the shaft 34 a, whereasthe link 28 b and a link 30 b are coupled rotatably on the other shaft34 b to form a parallel link mechanism.

[0026] The ascending/descending drive means on the upper blade portionside will now be described.

[0027] A trunnion type cylinder 37 is used as the ascending/descendingdrive means on the upper blade portion side. A trunnion portion of thetrunnion type cylinder 37 is coupled rotatably with a shaft 36 engagedwith a bracket 35 mounted on the carriage C frame 5. This trunnion typecylinder 37 is coupled with a link 33, constituting the upper and lowerblade portion link mechanism, through a tip end metal member 38 mountedat the tip end of a piston rod of the trunnion type cylinder 37 and ashaft 39 engaged with this tip end member 38.

[0028] The ascending/descending guide means for holding a clearancebetween the upper and lower blade portions will now be described.

[0029] In the above-described conventional apparatus, a guide bearing 40a and a guide bearing 40 b are provided in order to maintain therespective clearances between the leading plate cutting lower blade 6and the leading plate cutting upper blade 9 and between the trailingplate cutting lower blade 7 and the trailing plate cutting upper blade10 during the cutting operation as well as upon the cutting operation.Guide shafts 41 and 42 that may be movable in the vertical direction areprovided while being guided by these guide bearings 40 a and 40 b. Oneof the guide shafts 41 is provided on the lower side of one end side ofthe upper blade holder 11 and the other guide shaft 42 is provided onthe lower side of the other end side of the upper blade holder 11,respectively.

[0030] By the way, in the above-described conventional apparatus, sincethe trunnion type cylinder 37 is used as the ascending/descending meansfor moving the upper blade portion up and down, in the case where theupper blade holder (upper blade portion) 11 is to be moved up and downby feeding compressed air to this trunnion type cylinder 37, the densityof the used fluid is small. Accordingly, although the upper blade holder11 should be stopped at the top dead point and held in that position,there is a fear that the upper blade portion would be loweredunintentionally due to the leakage from the piston portion or the pistonrod portion of the interior of the trunnion type cylinder 37 or thepiping system or the like.

[0031] As shown in FIG. 14, in order to prevent this lowering movement,a safety lock mechanism is provided with a structure in which a pin 45mounted at a tip end of the piston rod of a cylinder 43 slidingly movingwithin a bracket 44 is normally inserted into a hole provided in thelink 33 constituting the above-described upper blade portionascending/descending means, and for example, if necessary (as desired),when the upper blade holder (upper blade portion) 11 is to be lowered toperform the cutting operation, the above-described cylinder 43 isoperated to pull the pin 45 apart from the hole of the link 33.

[0032] As described above, in the conventional cutting apparatus for awelding machine, two guide units as the ascending/descending guide meansguided by the guide bearings 12 a and 12 b and composed of the guideshafts 13 a and 13 b formed so as to be movable in the verticaldirection and two guide units as the ascending/descending guide meansguided by the guide bearings 26 a and 26 b and composed of the guideshafts 27 a and 27 b formed so as to be movable in the verticaldirection are used when the lower holder (lower blade portion) 8 ismoved up and down and when the upper blade holder (upper blade portion)11 are moved up and down, respectively.

[0033] In addition, as the ascending/descending guide means formaintaining the clearance for maintaining and holding the clearance ofthe cutting blades, the guide bearings 40 a and 40 b are providedbetween the lower holder (lower blade portion) 8 and the upper holder(upper blade portion) 11 and the two guide units composed of guideshafts 41 and 42 formed so as to be guided by these bearings and movablein the vertical direction are provided.

[0034] Thus, in such a conventional apparatus, since an excessive numberof guide units are used as the ascending/descending guide means betweenthe lower blade holder (lower blade portion) 8 and the upper bladeholder (upper blade portion) 11, the structure of the cutting apparatusfor a welding machine, i.e., the cutting apparatus for the mushroomwelding machine for metal plates in this case becomes complicated andexpensive in manufacture cost.

[0035] Also, in the case where a pneumatic system is used, for example,compressed air is fed to operate the trunnion type cylinder 37 as theascending/descending drive source for ascending/descending the upperblade holder (upper blade portion) 11, there is a problem in that theholder could not be stopped immediately by the compression property ofair when the upper blade holder 11 is to be stopped in emergency due tosome reason on the way of the ascending/descending operation thereof.

[0036] Also, in a manufacturing process of a welding machine, anexchange work for parts for maintenance or the like, in the case wherethe cutting lower blade and the cutting upper blade are assembled andthe clearance of the assembly thereof is adjusted or confirmed, it isimpossible to stop immediately the blades at a desired position due tothe compression property of air or it is also impossible to perform aninching operation or the like. For this reason, there is a problem thatit takes a large amount of labor for the adjustment or confirmation ofthe clearance.

SUMMARY OF THE INVENTION

[0037] In order to overcome the above-noted defects, an object of thepresent invention is to provide a cutting apparatus for a weldingmachine, which is simple in structure and superior in operationability.

[0038] According to a first aspect of the present invention, there isprovided a cutting apparatus for a welding machine, comprising a pair ofupper and lower blade portions facing to each other, an upper bladeportion ascending/descending link means for moving the upper bladeportion up and down to the lower blade portion, a plurality ofascending/descending guide means for guiding abutment between the upperand lower blade portions, and an ascending/descending drive means forascending/descending the upper blade portion through the upper bladeportion ascending/descending link means, characterized in that at leastone of each of the upper blade portion ascending/descending guide means,the lower blade portion ascending/descending guide means and theascending/descending guide means for holding a clearance between theupper and lower blade portions is used in common as a co-useascending/descending means out of the plurality of ascending/descendingguide means.

[0039] According to a second aspect of the present invention, thecutting apparatus for a welding machine according to the first aspect ofthe present invention is characterized in that the co-useascending/descending guide means engages end portions of the upper andlower blade portions movably up and down with a guide shaft provided inan apparatus frame so as to extend in parallel with an abutmentdirection of the upper and lower blade portions.

[0040] According to a third aspect of the present invention, there isprovided a cutting apparatus for a welding machine, comprising a pair ofupper and lower blade portions facing to each other, an upper bladeportion ascending/descending link means for moving the upper bladeportion up and down to the lower blade portion, a plurality ofascending/descending guide means for guiding the abutment between theupper and lower blade portions, and an ascending/descending drive meansfor ascending/descending the upper blade portion through the upper bladeportion ascending/descending link means, characterized by furthercomprising a hydraulic drive means normally depending upon the operationof the upper blade portion ascending/descending link means and workingas a drive source for the upper blade portion ascending/descending linkmeans when necessary, in conjunction with the upper blade portionascending/descending link means.

[0041] According to a fourth aspect of the present invention, thecutting apparatus for a welding machine according to the first or thesecond aspect of the present invention is characterized by furthercomprising a hydraulic drive means normally depending upon the operationof the upper blade portion ascending/descending link means and workingas a drive source for the upper blade portion ascending/descending linkmeans when necessary, in conjunction with the upper blade portionascending/descending link means.

[0042] According to a fifth aspect of the present invention, the cuttingapparatus for a welding machine according to the first or the secondaspect of the present invention is characterized by further comprising ahydraulic drive means normally depending upon the operation of the upperblade portion ascending/descending link means and working as a drivesource for the upper blade portion ascending/descending link means whennecessary, in conjunction with the upper blade portion.

[0043] According to a sixth aspect of the present invention, the cuttingapparatus for a welding machine according to the fifth aspect of thepresent invention is characterized in that at least oneascending/descending guide means other than the co-useascending/descending guide means is provided with guide hydraulic drivemeans, and a piston rod of a hydraulic cylinder as the guide hydraulicdrive means is used as a guide shaft.

[0044] According to a seventh aspect of the present invention, thecutting apparatus for a welding machine according to the fourth aspectof the present invention is characterized in that the hydraulic drivemeans is a hydraulic swing motor, and an output shaft of the swing motoris coupled detachably to the upper blade portion ascending/descendinglink means.

[0045] According to an eighth aspect of the present invention, thecutting apparatus for a welding machine according to the seventh aspectof the present invention is characterized in that the hydraulic swingmotor is provided with a solenoid valve for opening/closing a hydrauliccircuit of the swing motor so as to operate or stop the swing motor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In the accompanying drawings:

[0047]FIG. 1 is a frontal view of a cutting apparatus for a weldingmachine according to a first embodiment of the present invention;

[0048]FIG. 2 is a cross-sectional view taken along the line C-C of FIG.1;

[0049]FIG. 3 is a cross-sectional view taken along the line D-D of FIG.2;

[0050]FIG. 4 is a cross-sectional view of a second embodiment of thepresent invention corresponding to FIG. 2;

[0051]FIG. 5 is a frontal view of a cutting apparatus for a weldingmachine according to the second embodiment of the present invention;

[0052]FIG. 6 is a cross-sectional view taken along the line E-E of FIG.5;

[0053]FIG. 7 is a cross-sectional view taken along the line F-F of FIG.6;

[0054]FIG. 8 is a cross-sectional view taken along the line G-G of FIG.7;

[0055]FIG. 9 is a cross-sectional view of a fourth embodiment of thepresent invention corresponding to FIG. 2;

[0056]FIG. 10 is across-sectional view of a fifth embodiment of thepresent invention corresponding to FIG. 2;

[0057]FIG. 11 is a cross-sectional view of a sixth embodiment of thepres4ent invention corresponding to FIG. 2;

[0058]FIG. 12 is a frontal view showing a conventional cutting apparatusfor a welding machine;

[0059]FIG. 13 is a view taken along the line A-A of FIG. 12; and FIG. 14is a view taken along the line B-B of FIG. 13.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0060] Embodiment 1

[0061] A cutting apparatus for a seam welding machine in accordance witha first embodiment of the present invention will now be described withreference to FIGS. 1, 2 and 3. FIG. 1 is a frontal view, FIG. 2 is across-sectional view taken along the line C-C of FIG. 1 and FIG. 3 is across-sectional view taken along the line D-D of FIG. 2. Incidentally,in FIGS. 1, 2 and 3, the same reference numerals are used to indicatethe components or members having the same function and structure inFIGS. 12 to 14, and explanation therefor will be omitted.

[0062] An ascending/descending means for guiding abutment between anupper blade and a lower blade will now be described with reference toFIGS. 1 and 2.

[0063] First of all, on the side of the lower blade portion, a guideunit as the ascending/descending guide means composed of a guide bearing12 a mounted on a carriage C frame 5 as the apparatus frame and a guideshaft 13 a guided by the guide bearing 12 a for guiding one end of thelower blade holder 46 movably in the vertical direction is provided atone end side of the lower blade holder 46 as the lower blade portion.

[0064] Also, another guide unit as the ascending/descending guide meansfor the lower blade holder 46, i.e., the ascending/descending means isprovided on the other end side of the above-described lower holder 46.

[0065] This guide unit is a co-use ascending/descending means and iscomposed of a bracket 47 and a bracket 48 mounted on the carriage Cframe 5 and a guide shaft 49 fixed in the vertical direction by thebracket 47 and the bracket 48. The end portion of the other end side ofthe lower blade holder 46 is guided by the guide shaft 49 of this co-useascending/descending guide means and engaged movably in the verticaldirection.

[0066] On the other hand, on the side of the upper blade portion, aguide unit as the ascending/descending guide unit composed of a guidebearing 26 a mounted on the carriage C frame 5 as the apparatus frameand a guide shaft 27 a guided by the guide bearing 26 a for guiding oneend of an upper blade holder 50 movably in the vertical direction isprovided at one end side of the upper blade holder 50 as the upper bladeportion.

[0067] Also, on the other end side of the above-described upper bladeholder 50, the upper blade portion is guided by the guide shaft 49 ofthe above-described co-use ascending/descending guide means mounted onthe carriage C frame 5 and is movable in the vertical direction.

[0068] Namely, the other end portion of the upper blade holder 50 usesthe co-use ascending/descending guide means in common for theabove-described lower blade holder 46.

[0069] A clearance holding means of the upper and lower blade portionwill now be described.

[0070] This clearance holding means is the ascending/descending guidemeans provided with a structure for maintaining and holding therespective clearance between a leading plate cutting lower blade 6 and aleading plate cutting upper blade 9 and between a trailing plate cuttinglower blade 7 and the trailing plate cutting upper blade 10 upon thecutting operation.

[0071] In the example shown, the guide shaft 40 a is provided upwardlyon the upper side of one end of the lower blade holder 46 as the lowerblade portion and the guide shaft 41 is provided downwardly on the lowerside of the one end side of the upper blade holder 50 to be guided bythe guide bearing 40 a and movable in the vertical direction.

[0072] An ascending/descending drive means for ascending/descending theupper blade portion through the above-described upper blade portionascending/descending link means will now be described.

[0073] In this first embodiment, a trunnion type cylinder 37 is used asthe ascending/descending drive means. Compressed air is fed to thistrunnion type cylinder 37 to move up and down the upper blade holder 50as the upper blade portion.

[0074] A hydraulic drive means as a drive source for the upper bladeascending/descending link means when necessary and normally dependingupon the operation of the upper blade ascending/descending link meanswill now be described in conjunction with the upper bladeascending/descending link means constituting the ascending/descendingmeans.

[0075] In this hydraulic drive means, a trunnion portion of a hydraulictrunnion type cylinder 53 is coupled rotatably with a shaft 52 fitted ina bracket 51 mounted on the top surface side of the carriage C frame 5as the apparatus frame, and at the same time, a link 56 constituting theupper blade portion ascending/descending link means is coupled rotatablywith a tip end member made by metal 54 mounted at a tip end of a pistonrod of the above-described hydraulic trunnion type cylinder 53 and ashaft 55 fitted in the tip end member made by metal 54.

[0076] A control of this hydraulic drive means will now be described.

[0077] A pipe 57 is connected to one piping port of a hydraulic “openingand closing” solenoid valve (hereinafter also referred to asopening/closing valve) from one piping port of the hydraulic trunniontype cylinder 53 as the hydraulic drive means, and a pipe 59 isconnected to the other piping port of the opening/closing valve 58 fromthe other piping port of the hydraulic trunnion type cylinder 53,respectively, to form a hydraulic circuit.

[0078] Of course, hydraulic working oil is filled in these hydraulictrunnion type cylinder 53, pipe 57, opening/closing valve 58 and pipe59.

[0079] Incidentally, in the case where the compressed air is fed to theabove-described trunnion type cylinder 53 to perform the up-and-downmovement of the upper blade holder, it is possible to use the followingarrangement. Two feed ports are coupled with each other by a pipe. Thefixed object is connected to a hydraulic cylinder provided with ahydraulic opening and closing solenoid valve in the midway of the pipe,an object for the up-and-down movement of the hydraulic swing motor, anobject depending upon the up-and-down movement or a rotary shaft of thelink mechanism. By utilizing non-compression property of the oil, theobjects are stopped immediately during the up-and-down movement of theupper blade holder by the closing operation of the solenoid valve tohold the position.

[0080] In this first embodiment, since an upper holder 11 as the upperblade portion may be held and moved up and down by the twoascending/descending means of the guide shaft 29 and the guide bearing26 a, it is possible to reduce the number of the guide units as theascending/descending means by one. It is easy to perform the maintenanceand confirmation work in comparison with the conventional work foradjusting the three guide units as the ascending/descending means.

[0081] Also, the hydraulic drive means is provided additionally to thelink 56 constituting the upper blade portion ascending/descending linkmeans of the ascending/descending means to form the hydraulic circuit asa control circuit composed of the hydraulic trunnion type cylinder 53 asthe above-described hydraulic drive means, its pipe 59, theopening/closing valve (solenoid valve) 58 and the like. Accordingly, forinstance, even if the self-holding function is eliminated due to theabsence of the pneumatic pressure, it is possible to maintain theup-and-down operation by the above-described hydraulic drive meanscomposed of the hydraulic trunnion type cylinder 53 and theopening/closing valve 58, and in addition, it is possible to stop theoperation of the upper holder 11 as the upper blade portion.Accordingly, it is possible to provide circumstances that are veryeffective for the maintenance and adjustment work.

[0082] Embodiment 2

[0083] A second embodiment will now be described with reference to FIG.4. In this second embodiment, while modifying the foregoing embodiment,in conjunction with the upper blade portion ascending/descending linkmeans, a hydraulic foot cylinder 60 as hydraulic drive means to worknormally to depend upon the operation of the above-describedascending/descending link means and to work as a drive source of theupper blade ascending/descending link means when necessary is usedinstead of the hydraulic trunnion type cylinder 53. A tip end of apiston rod of the hydraulic trunnion type cylinder 53 is directlycoupled with the upper blade holder 50 as the upper blade.

[0084] The hydraulic circuit for controlling this hydraulic drive meansis constructed in the same manner as in the first embodiment with thelike operation and the like effect.

[0085] Namely, the upper blade holder 50 may be held by the small numberof the ascending/descending means by one in comparison with theconventional case. Even if the cylinder 37 as the ascending/descendingdrive means for moving the upper blade portion up and down is of apneumatic type and the pneumatic pressure is eliminated due to the stopof electric supply or the like, the upper blade holder 50 is held in itsposition in the same manner as in the first embodiment by the hydrauliccircuit constituted by the hydraulic cylinder 60 to thereby perform themore safety maintenance and adjustment work.

[0086] Embodiment 3

[0087] In a third embodiment, while modifying the first and secondembodiments, it is possible to perform the self-holding function, thatis, to hold the upper blade portion in any desired position by stoppingthe operation of the ascending/descending link means by using thehydraulic swing motor as the hydraulic drive means to work as theascending/descending drive source of the upper blade portion whennecessary and to work normally to depend on the operation of the upperblade portion in conjunction with the upper blade portion.

[0088] The third embodiment will now be explained with reference toFIGS. 5 to 8. FIG. 5 is a frontal view, FIG. 6 is a cross-sectional viewtaken along the line E-E of FIG. 5, FIG. 7 is a cross-sectional viewtaken along the line F-F of FIG. 6, and FIG. 8 is a cross-sectional viewtaken along the line G-G of FIG. 7.

[0089] Incidentally, in FIGS. 5 to 8, the same reference numerals areused to indicate the same components or members as those in the first tothird embodiments (FIGS. 1 to 7). Accordingly, the explanation thereforwill be omitted.

[0090] First of all, an ascending/descending guide means will bedescribed.

[0091] In the case where compressed air is fed to a trunnion typecylinder 37 as an ascending/descending drive means and the upper bladeholder 50 as the upper blade portion is moved up and down, the one endside of the upper blade holder 50 is guided by the ascending/descendingguide means composed of a guide bearing 26 a mounted on the carriage Cframe 5 as the apparatus frame and a guide shaft 27 a provided movablyin the vertical direction and guided by this guide bearing 26 a.

[0092] On the other hand, the other end side of the upper blade holder50 is used in common as the co-use ascending/descending guide means asthe ascending/descending guide means for the lower blade holder 46 asthe lower blade portion.

[0093] Namely, the upper blade holder 50 is fitted to the guide shaft 49fixed by the bracket 47 and the bracket 48 mounted on theabove-described carriage C frame 5 and is guided by the guide shaft 49movably in the vertical direction in the same manner as in FIGS. 4 to 6.This co-use ascending/descending guide means has the same structure asthat of the foregoing embodiments.

[0094] An ascending/descending link means will now be described.

[0095] One end side of a link 28 a constituting the upper bladeascending/descending link means of the ascending/descending link meansis coupled rotatably with a shaft 29 a fitted on the upper side of oneend side of the upper holder 50 as the upper blade portion, whereas theother end side of a link 28 b is coupled rotatably with a shaft 29 bfitted on the upper side of the other end side of the upper blade holder50.

[0096] Also, one end side of a link 62 constituting the upper bladeportion ascending/descending link is coupled with a shaft 63 engagedwith a bracket 31 a mounted on the upper side of the carriage C frame 5as the apparatus frame so as to make it possible to transmit the torquethrough a key 64.

[0097] In the same manner, one end side of a link 30 b constituting theupper blade portion ascending/descending link is coupled rotatably witha shaft 32 b engaged with a bracket 31 b mounted on the upper side ofthe carriage C frame 5.

[0098] An ascending/descending drive means for moving the upper bladeportion up and down will now be described.

[0099] A shaft 34a and a shaft 34 b are provided to a link 33constituting the upper blade portion ascending/descending link, and thelink 63 and the link 30a are coupled rotatably with the shaft 34 a andthe link 28 b and the link 30 b are coupled rotatably with the shaft 34b to form the parallel link mechanism.

[0100] Also, in this link 33, a trunnion portion of the trunnion typecylinder 37 is coupled rotatably with a shaft 36 engaged with a bracket35 mounted on the carriage C frame 5 as the apparatus frame, through atip end member 38 mounted at the tip end of a piston rod of the trunniontype cylinder 37 and a shaft 39 engaged with this tip end member 38.

[0101] Thus, the upper blade ascending/descending link constituting theascending/descending link means is driven by the trunnion type cylinder37 as the ascending/descending drive means so that the upper bladeportion is raised to the lower blade portion.

[0102] A hydraulic drive means as a drive source for the upper bladeascending/descending link means when necessary and normally dependingupon the operation of the upper blade ascending/descending link meanswill now be described in conjunction with the upper bladeascending/descending link means. In this third embodiment, the hydraulicswing motor is used as the hydraulic drive means.

[0103] In FIG. 7, the hydraulic swing motor 68 is provided on thecarriage C frame 5 as the apparatus frame and constructed so that itsoutput shaft transmits the torque through the key 67, the shaft joint 66and the key 65 to the shaft 63 (FIG. 6) of the link 62 of the upperblade portion ascending/descending link means constituting theascending/descending link means.

[0104] Control of this hydraulic swing motor 68 will now be described.

[0105] In FIG. 8, a pipe 69 is connected to one piping port of ahydraulic “opening and closing” solenoid valve 58 as an opening/closingvalve from one piping port of the hydraulic swing motor 68, and a pipe70 is connected to the other piping port of the hydraulicopening/closing solenoid valve 58 from the other piping port of thehydraulic swing motor 68, respectively, to form a hydraulic circuit asthe control circuit.

[0106] Of course, the hydraulic working oil is filled in the hydraulicswing motor 68, pipe 69, hydraulic opening/closing solenoid valve 58 andpipe 70.

[0107] In accordance with the third embodiment, even if the cylinder 37as the ascending/descending means is of a pneumatic type and it isdifficult to maintain the self-holding function of the cylinder 37 dueto the shortage of the pneumatic pressure caused by the stop of electricsupply, if a solenoid valve having a port that is to be closed when theelectric supply is stopped is used as the opening/closing valve, thelatter is closed to stop the rotation of the swing motor. Accordingly,it is possible to stop the movement of the upper blade portionascending/descending means through the rotary shaft 63 and the link 62,and it is possible to stop the up-and-down movement of the upper bladeportion.

[0108] Incidentally, since the opening/closing valve (solenoid valve) 58is opened in the normal operation, the swing motor is operateddependently, and there is no harm against the operation of the upperblade holder 50.

[0109] Also, according to the third embodiment, it is possible to reducethe number of the guide units as the ascending/descending means by onein comparison with the conventional case.

[0110] Embodiment 4

[0111] In a fourth embodiment, while improving the foregoing secondembodiment (FIG. 4), in the second embodiment, at least oneascending/descending guide means out of other ascending/descending guidemeans than the co-use ascending/descending guide means is provided witha guide hydraulic drive means having the ascending/descending operationadjusting function, and a piston rod of the hydraulic cylinder as theguide hydraulic drive means is used as a guide shaft for theascending/descending guide means. This will now be described withreference to FIG. 9.

[0112] In FIG. 9, a hydraulic cylinder 83 as the guide hydraulic drivemeans is disposed on the upper side of the carriage C frame 5 as theapparatus frame, and its piston rod 82 is passed through the carriage Cframe 5 and extended to the lower blade portion side from the upperblade portion side in parallel with the abutment direction of the upperand lower blade portions.

[0113] The piston rod 82 is supported to be movable up and down by aguide member 81 within the upper blade holder 11 as the upper bladeportion or a guide member 80 within the carriage C frame 5.

[0114] Then, a tip end (lower end portion) of the piston rod 82 isprovided to be insertable into the guide bearing 12 a provided in thelower blade portion before the cutting operation.

[0115] According to the fourth embodiment, it is possible to dispensewith the guide bearing for the upper blade holder 11. Namely, prior tothe start of the cutting operation, the piston rod 82 of the guidehydraulic cylinder 83 is lowered and inserted into the guide bearing 12a.

[0116] At this time, the upper blade holder 50 is bound by the guideshaft 49 of the co-use ascending/descending guide means and the pistonrod 82 and maintained thereby. Incidentally, the concept to hold theposition of the upper blade portion is the same as that of the firstembodiment.

[0117] Also, in this fourth embodiment, the guide bearing is used incommon for the ascending/descending means, the upper blade portion andthe lower blade portion. Accordingly, if this is applied to the first tothird embodiments, it is possible to further dispense with theascending/descending guide means by one in each embodiment. As a result,it is possible to simplify the maintenance and adjustment work.

[0118] Embodiment 5

[0119] A fifth embodiment relates to the improvement in the secondembodiment (FIG. 4). A piston rod of a hydraulic cylinder 60 ashydraulic drive means having the ascending/descending operationadjusting function is supported movably up and down by a guide member 80installed within the carriage C frame 5 as the apparatus frame. Theother structure is the same as that of the second embodiment.

[0120] According to the fifth embodiment, it is possible to dispensewith the guide bearing for the upper blade holder 11 as the upper bladeportion.

[0121] Namely, in FIG. 11, the upper blade holder 50 is guided by thepiston rod of the hydraulic cylinder 60 as the hydraulic drive means formaintaining the position and the guide shaft 49 of the co-useascending/descending guide means and may be moved up and down by thecylinder 37 as the ascending/descending drive means.

[0122] During the normal operation, the piston rod of the hydrauliccylinder 60 may be moved dependently upon the up-and-down movement ofthe upper blade holder 50 by magnetically exciting the solenoid valve 58as the opening/closing valve.

[0123] However, when necessary, for example, in the case where theelectric supply is interrupted due to the stop of the electric supply,the solenoid valve 58 is closed so that the hydraulic cylinder 58 doesthe self-holding function. As a result, the upper blade holder 50 isheld in place.

[0124] Embodiment 6

[0125] A sixth embodiment 6 is an improvement in the fifth embodiment 5(FIG. 10). While modifying the fifth embodiment, the rigidity of theguide member 80 is enhanced, and the ascending/descending guide meansfor holding a clearance may be dispensed with in addition to the guidebearing for the upper blade holder.

[0126] Namely, in FIG. 11, the upper blade holder 50 as the upper bladeportion is guided only by the piston rod of the hydraulic cylinder 60 asthe hydraulic drive means for holding the position and the guide shaft49 of the co-use ascending/descending guide means, and the guide bearingfor setting up the clearance is dispensed with.

[0127] For this reason, in comparison with the machine structure as inthe above-described fifth embodiment of FIG. 10, it is possible toreduce the parts which needs maintenance. Incidentally, the positionalholding of the upper blade portion is exactly the same as that of theabove-described fifth embodiment.

[0128] According to the first to eighth aspects of the presentinvention, at least one ascending descending guide means may be used incommon out of the large number of ascending/descending guide meansprovided between the upper and lower blade portions to thereby reducethe total number of the ascending/descending guide means and to providea cutting apparatus for a welding machine that is simple in structureand less expensive.

[0129] According to the third to eighth aspects of the presentinvention, in an apparatus using a pneumatic cylinder as theascending/descending drive means for moving the upper blade portion upand down, the upper blade portion may be held in any desired position byusing the hydraulic drive means. Accordingly, for example, it ispossible to effect the emergency stop and to perform the inchingoperation, and in addition, it is possible to provide a cuttingapparatus for a welding machine that has a high performance also with afunction of a safety lock mechanism for holding the position of theupper blade portion moving upwardly.

What is claimed is:
 1. A cutting apparatus for a welding machinecomprising a pair of upper and lower blade portions facing to eachother, an upper blade portion ascending/descending link means for movingthe upper blade portion up and down to the lower blade portion, aplurality of ascending/descending guide means for guiding abutmentbetween the upper and lower blade portions, and an ascending/descendingdrive means for ascending/descending the upper blade portion throughsaid upper blade portion ascending/descending link means, wherein atleast one of each of the upper blade portion ascending/descending guidemeans, the lower blade portion ascending/descending guide means and theascending/descending guide means for holding a clearance between theupper and lower blade portions is used in common as a co-useascending/descending means out of said plurality of ascending/descendingguide means.
 2. The cutting apparatus for a welding machine, accordingto claim 1 , wherein said co-use ascending/descending guide meansengages end portions of the upper and lower blade portions movably upand down with a guide shaft provided in an apparatus frame so as toextend in parallel with an abutment direction of the upper and lowerblade portions.
 3. A cutting apparatus for a welding machine, comprisinga pair of upper and lower blade portions facing to each other, an upperblade portion ascending/descending link means for moving the upper bladeportion up and down to the lower blade portion, a plurality ofascending/descending guide means for guiding the abutment between theupper and lower blade portions, and an ascending/descending drive meansfor ascending/descending the upper blade portion through said upperblade portion ascending/descending link means, further comprising ahydraulic drive means normally depending upon the operation of saidupper blade portion ascending/descending link means and working as adrive source for said upper blade portion ascending/descending linkmeans when necessary, in conjunction with said upper blade portionascending/descending link means.
 4. The cutting apparatus for a weldingmachine, according to claim 1 , further comprising a hydraulic drivemeans normally depending upon the operation of said upper blade portionascending/descending link means and working as a drive source for saidupper blade portion ascending/descending link means when necessary, inconjunction with said upper blade portion ascending/descending linkmeans.
 5. The cutting apparatus for a welding machine, according toclaim 1 , further comprising a hydraulic drive means normally dependingupon the operation of said upper blade portion ascending/descending linkmeans and working as a drive source for said upper blade portionascending/descending link means when necessary, in conjunction with saidupper blade portion.
 6. The cutting apparatus for a welding machine,according to claim 5 , wherein at least one ascending/descending guidemeans other than the co-use ascending/descending guide means is providedwith a guide hydraulic drive means, and a piston rod of a hydrauliccylinder as said guide hydraulic drive means is used as a guide shaft.7. The cutting apparatus for a welding machine, according to claim 4 ,wherein the hydraulic drive means is a hydraulic swing motor, and anoutput shaft of said swing motor is coupled detachably to the upperblade portion ascending/descending link means.
 8. The cutting apparatusfor a welding machine, according to claim 7 , wherein the hydraulicswing motor is provided with a solenoid valve for opening/closing ahydraulic circuit of the swing motor so as to operate or stop the swingmotor.